This invention relates to brake disks and pertains more particularly to a disk keyslot reinforcement that is affixed to the disk in a manner which eliminates drilled-through holes in the material comprising the disk structure.
While the keyslot reinforcement concept of this invention may be applied to a disk of any material structure, the increased use of carbon disks in aircraft and other type disk brake assemblies has necessitated design configurations for keyslot reinforcements to compensate for structural limitations in such carbon disks. Exemplary of the prior art keyslot reinforcements are those described and illustrated in the following U.S. patents: U.S. Pat. No. 3,904,000 to R. E. Berger; U.S. Pat. No. 3,907,076 to R. L. Crossman, et al; U.S. Pat. No. 3,927,740 to R. L. Zarembka; and U.S. Pat. No. 4,007,814 to R. E. Berger.
The use of keyslot reinforcements of the type described in the above-mentioned patents has resulted in improved carbon disk life, however, conventional methods of affixing such reinforcements to the peripheral edge of the disk have not been totally satisfactory. This is because of (a) the increased weight of the reinforcements due to longer legs to accommodate drilled-through holes in the disk, (b) the high reaction forces present in the holes due to a greater moment arm, (c) the special tolerances and/or hole geometries necessary to alleviate thermal expansion forces, and (d) fatigue failure and/or excessive loosening of the reinforcements which results due to the lack of restrainment at the keyslot itself. Furthermore, the reinforcements of the prior art are of necessity made of special heat resistant alloys. These alloys are required to maintain the structural strength of the reinforcements for reasonable service life at elevated temperatures under the above-mentioned loading conditions, however, such alloys are not easily hardened. This, of course, results in excessive wear at the wheel key-to-keyslot reinforcement interface. In addition, the relatively thin section thickness of currently stamped steel reinforcements is not sufficiently flat and rigid to uniformly transmit braking torque forces into the carbon material surrounding the slot which carries the reinforcement. This results in localized area of compressive failure which reduces the required bearing area of the carbon material.